The interplay of colours on the facade between the white-painted concrete and the dark panelling is thus the most visible indication that every effort has been made to squeeze as many kWh out of the building as possible.
The large, black panels on the closed balconies along the facade and on the south-facing gable conceal 203 m² of PV panelling. Normally, the building owner will choose to install solar PV panels only on the roof, which is both the most effective and the least visible place. The challenge, however, is that as soon as a building is more than two storeys high it becomes difficult to produce enough solar energy on the roof surface to cover the building’s consumption. Which was why it was clear from the beginning that it would be necessary also to place PV panels on the facade.
From the architectural point of view it was a relatively simple exercise to locate solar panels on the SW-facing gable. It was mainly a question here of having solar panels made to dimensions great enough to cover the facade surfaces between the gable windows.
Among the black panels a few white rectangles peek out to offer an interplay of colours against the dark surfaces. One small example of how the dogmas – in this case energy requirements and architecture – are constantly challenging each other, needing care and consideration in striking the right balance.
Uniting output and aesthetics
In addition to being able to meet the ambitious target of energy neutrality the power plant also had to live up to the architect’s aesthetic demands:
Normally, a photovoltaic (PV) panel consists of a glass plate, a strong aluminium frame around the glass, and a box mounted at the rear containing large bypass diodes to prevent hotspots.
In the design of the HOUSING+ PV panels it has been possible to mould the installation fittings directly into the panel – avoiding the need for both the aluminium frame and the rear-mounted box. The absence of any box at the rear also means that the cables can emerge at any suitable point. Thus large modules can be adapted to the architecture instead of vice versa.
This production method also means that the panel is significantly slimmer and easier to install. It simply hooks onto a rail on the facade. This technique was a key factor in being able to manufacture PV panels to suit the requirements of the HOUSING+ project.
To ensure stable and safe installation of the large panels without unsightly aluminium frames, the architect and solar panel supplier developed a new type of installation fitting which underwent extensive tests at the hands of experts from the Technical University of Denmark.
Invisible solar panels
The panels were required to be non-reflective, black and without the characteristic blue-violet surface sheen. Broadly speaking, the panels had to be invisible.
For this reason, special black silicone cells were developed for the interior of the module, behind a black background foil. At the same time thin, black strips were specially developed for placing on top of the three metal strips that are otherwise visible in each PV panel. Both of these adaptations were compromises made in the name of aesthetics – which has very slightly reduced the photovoltaic effect.